This invention relates generally to rotary machines, and more particularly to methods and apparatus for fabricating components of rotary machines.
At least some known rotary machines such as, but not limited to, steam turbine engines and/or gas turbine engines, include various rotor assemblies such as, but not limited to, a fan, a compressor, and/or turbines that each includes a rotor assembly. At least some known rotor assemblies include components such as, but not limited to, disks, shafts, spools, bladed disks (“blisks”), seals, and/or bladed integrated rings (“blings”). Such components may be subjected to different temperatures depending on an axial position and/or a radial position within the gas turbine engine.
For example, during operation, at least some known gas turbine engines may be subjected to an axial temperature gradient that extends along a central rotational axis of the engine. Generally gas turbine engine components are exposed to lower operating temperatures towards a forward portion of the engine and higher operating temperatures towards an aft portion of the engine. As such, known rotor assemblies and/or rotor components are generally fabricated from materials capable of withstanding an expected maximum temperature at its intended position within the engine. At least some other known gas turbine engines may be subjected to radial temperature gradients that extend generally along radial axes that are perpendicular to a central rotational axis of the engine. Different radial areas of the respective assembly/component are subjected to different temperatures. For example, radially inward portions of such engines are generally exposed to lower operating temperatures than components located relatively radially outward.
To accommodate different temperatures, engine components have been fabricated with different alloys that have different material properties that enable the components to withstand different expected maximum radial and/or axial temperatures. More specifically, known rotary assemblies and/or rotary components are generally forged from a single alloy that is capable of withstanding the expected maximum temperature of the entire rotary assembly and/or rotary component. Because single alloys that are capable of withstanding the expected maximum temperature are generally more expensive and heavier than alloys that are only capable of withstanding lower temperatures, known rotary components forged from the more expensive and heavier single alloys generally increase the overall weight and/or cost of the rotor components as compared to rotary components fabricated from alloys that are only capable of withstanding lower temperatures.
Known forging methods may also require a greater amount of input forging material than is necessary to produce a finished part to facilitate material flow for die fill. Moreover, additional machining time may be required to remove extra material after forging. As such, known forging methods may also increase the overall cost of fabricating the rotor components.